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Ragwort

Back in 2007, having previously hosted a number of school visits, we had an approach to provide visits and gardening work experience for adults with learning difficulties. As is now the general malaise, any visits were preceeded by a risk assessment. We were suprised to then receive a letter, explaining that it would not be possible for these adults to visit the site because of the presence of Ragwort, as this might pontentially poisin one of the students if ingested.

Ragwort and Cinnabar Moth catterpillar - Aug 2002

Ragwort and Cinnabar Moth catterpillar - Aug 2002

The wild part of our garden is planted with great care to increase the biodiversity of the area. Ragwort is a native British plant, and supports 177 insects and numerous fungi. The Cinnabar moth is amongst those that rely exclusively on Ragwort for laying eggs, and the catapillars absorb alkalides from the plants, making them distatesful to birds.

It is known that Ragwort can be poisinous to horses. They will generally avoid it, unless hidden dried in hay. Statistics are thrown about, and wild claims made about how toxic Ragwort is, but it is worth reading the science at http://www.ragwortfacts.com/ragwort-horse-deaths.html, which suggests that there are very few documented deaths of horses from this cause.

Horse societies, and the occasional news reports, call for total eradication of Ragwort from the UK. We certainly do not intend to graze any animals on our site, nor to our knowledge are any near neighbours, and we are keen to see both the Cinnabar caterpillar and moth on site.

And as to human risks – it is estimated that one person would have to eat around 14lbs of the plant to achieve a lethal dose. Pretty determined grazing on a plant that we just do not have in that quantity. And anyhow, around 3% of plants also contain Alkalides, the active chemical of concern.

And whilst Ragwort is mentioned in the Weeds Act of 1959, that empowers parliament to order suppression of weeds where these have become a problem, not universal eradication. The following are the named weeds;

  • spear thistle (cirsium vulgare (Savi) Ten.),
  • creeping or field thistle (cirsium arvense(L.) Scop.),
  • curled dock (rumex crispusL.),
  • broad-leaved dock (rumex obtusifoliusL.), and
  • ragwort (senecio jacobaeaL.);

Sadly, though we pointed these things out to the teacher who had undertaken the risk assessment, their students did not come. We don’t especially cultivate Ragwort, or thistles, but we do co-exist with some.